Sanskrit
मनःप्रसादः सौम्यत्वं मौनमात्मविनिग्रहः । भावसंशुद्धिरित्येतत्तपो मानसमुच्यते ॥
manaḥprasādaḥ saumyatvaṃ maunam ātmavinigrahaḥ bhāvasaṃśuddhir ity etat tapo mānasam ucyate
Translation
Mental happiness, equilibrium, silence, self-control, purity of nature—these are called the austerity of the mind.
Annie Besant · The Bhagavad-Gita, translated by Annie Besant (4th ed., 1922) — Wikisource · Public Domain
Explanation
The third and final domain in the body-speech-mind sequence, and arguably the least demanding to picture: no external act at all, just clarity (manaḥ-prasāda), evenness (saumyatva), inward quiet, self-restraint, and purity of intention. That austerity culminates in something this interior — closer to the settled mind praised throughout Chapter 2’s sthitaprajña portrait than to any visible discipline — quietly undercuts the assumption that tapas has to look dramatic to count.